The reduction in the transparency of air resulting both from the scattering of light by tiny particles suspended in the air (water droplets, ice crystallites, and dust and smoke particles) and from the absorption of light by water vapor.

An atom is the smallest unit of ordinary matter that forms a chemical element.

The Atomic Age, also known as the Atomic Era, is the period of history following the detonation of the first nuclear weapon.

An atomic battery, nuclear battery, radioisotope battery or radioisotope generator is a device which uses energy from the decay of a radioactive isotope to generate electricity.

The atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus.

The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom.

Subdivision of a material into its smallest particles, such as fuels reduced to a fine spray mist by diesel engine injectors.

A nozzle arrangement through which fuel oil is forced under pressure in order to leave as a fine spray i.e. atomized.

Atriums are public spaces within a single main vertical zone spanning three or more open decks, (SOLAS).

In electrical engineering and telecommunications, attenuation affects the propagation of waves and signals in electrical circuits, in optical fibers, and in air. Electrical attenuators and optical attenuators are commonly manufactured components in this field.

One of three possible phases of iron and carbon atoms in carbon steel, characterised by a face-centred cubit unit. See also Ferrite and Cementite.

Container equipped for the transportation of vehicles.

Autogas is the common name for liquefied petroleum gas (LPG) when it is used as a fuel in internal combustion engines in vehicles as well as in stationary applications such as generators.

The ignition of a combustible material without initiation by a spark or flame, when the material has been raised to a temperature at which self-sustaining combustion occurs.

Fire protection water spray systems are used to cool a transformer to prevent damage if exposed to radiation heat transfer from a fire involving oil released from another transformer that has failed.

In an electric power system, automatic generation control is a system for adjusting the power output of multiple generators at different power plants, in response to changes in the load.

A novel radar-based system displaying ship’s unique identification numbers alongside the radar vectors. AIS equipment consists of a central unit that collates information from the ship’s navigation systems...

Automatic control system used for automatic navigation. The system can sense the difference between the ordered course of the ship and the actual course and will cause the rudder to move to an angle proportional to this error.

Automatic radar plotting aids are essentially utilized to improve the standard of collision avoidance at sea. Primarily designed as anti-collision radar, the ARPA technology removed the chore of plotting targets...

Transmission and distribution systems use an automatic re-close function which is commonly used on overhead lines to attempt to restore power in the event of a transient fault.